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1297 lines
37 KiB
1297 lines
37 KiB
//+-------------------------------------------------------------------------
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//
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// Copyright (C) 1991, Microsoft Corporation.
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//
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// File: FA.cxx
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//
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// Contents: Non-deterministic finite automata
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//
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// Classes: CNFA
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//
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// History: 01-20-92 KyleP Created
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// 03-11-97 arunk Modified for Kessel
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//--------------------------------------------------------------------------
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#include <fa.hxx>
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#include <stateset.hxx>
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//+-------------------------------------------------------------------------
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//
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// Member: CFA::CFA, public
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//
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// Synopsis: Copy constructor
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//
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// History: 13-Jul-95 KyleP Created
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//
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//--------------------------------------------------------------------------
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CFA::CFA( CFA const & src )
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: _cTotal( src._cTotal ),
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_ppState( 0 )
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{
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_ppState = new CFAState * [ _cTotal ];
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unsigned i = 0;
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for ( ; i < _cTotal; i++ )
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{
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if ( 0 == src._ppState[i] )
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_ppState[i] = 0;
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else
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_ppState[i] = new CFAState( *src._ppState[i] );
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}
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFA::~CFA, protected
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//
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// Synopsis: Frees automata.
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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CFA::~CFA()
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{
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if( _ppState )
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{
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for ( UINT i = 0; i < _cTotal; i++ )
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{
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delete _ppState[i];
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}
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delete _ppState;
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}
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFA::Add, protected
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//
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// Synopsis: Adds new state to automata.
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//
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// Arguments: [pState] -- New state. State number is member data.
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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void CFA::Add( CFAState * pState )
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{
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if ( pState->StateNumber() > _cTotal )
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{
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for( UINT newTotal = (_cTotal) ? _cTotal * 2 : 1;
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pState->StateNumber() > newTotal;
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newTotal *= 2 );
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CFAState ** oldState = _ppState;
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_ppState = new CFAState * [ newTotal ];
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memcpy( _ppState, oldState,
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_cTotal * sizeof( CFAState * ) );
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memset( _ppState + _cTotal,
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0,
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(newTotal - _cTotal) * sizeof( CFAState * ) );
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_cTotal = newTotal;
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}
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_ppState[pState->StateNumber() - 1] = pState;
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFA::Get, protected
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//
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// Arguments: [iState] -- State to fetch.
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//
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// Returns: State [iState].
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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CFAState * CFA::Get( UINT iState ){
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return( _ppState[ iState - 1 ] );
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::CNFA, public
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//
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// Synopsis: Converts regular expression string to NFA.
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//
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// Arguments: [pwcs] -- Regular expression.
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// [fCaseSens] -- true if case sensitive search.
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//
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// History: 20-Jan-92 Kyleap Created
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//
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//--------------------------------------------------------------------------
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CNFA::CNFA( WCHAR const * pwcs, bool fCaseSens )
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: _iNextState( 1 ),
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_iStart( 0 ),
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_chars( fCaseSens ),
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_pState( 0 )
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{
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UINT iEnd;
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//
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// _pState initially contains room for 2 * #chars in regex. According
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// to the Dragon Book pg. 121 this is guaranteed to be sufficient space.
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// Of course the dragon book doesn't completely take DOS or CMS into
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// account. For DOS, we need to treat beginning (and end) of line as
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// 'characters' in the string. For CMS, I agreed to support the
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// {m,n} construct, which clearly violates this rule.
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//
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if ( 0 == pwcs )
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{
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throw ERROR_INVALID_PARAMETER;
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}
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_cState = wcslen( pwcs ) * 2 + 2*2; // 2*2 for beginning & end of line
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_pState = new CNFAState [ _cState ];
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for ( unsigned i = 1 ; i <= _cState; i++ )
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Get(i)->Init(i);
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FindCharClasses( pwcs );
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Parse( pwcs, &_iStart, &iEnd );
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Get( iEnd )->MakeFinal();
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::CNFA, public
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//
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// Synopsis: Copy constructor
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//
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// Arguments: [src] -- Source
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//
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// History: 13-Jul-95 Kylep Created
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//
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//--------------------------------------------------------------------------
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CNFA::CNFA( CNFA const & src )
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: _iNextState( src.NumStates() ),
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_iStart( src._iStart ),
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_chars( src._chars ),
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_cState( src._cState ),
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_pState( new CNFAState [ src._cState ] )
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{
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for ( unsigned i = 0; i < _cState; i++ )
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_pState[i] = src._pState[i];
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::~CNFA, public
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//
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// Synopsis: Free state table.
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//
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// History: 13-Oct-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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CNFA::~CNFA()
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{
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delete [] _pState;
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::EpsClosure, public
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//
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// Synopsis: Computes the epsilon closure for state [StateNum]
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//
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// Effects: States in the epsilon closure of state [StateNum]
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// are added to the state set [ssOut].
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//
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// Arguments: [StateNum] -- Initial state.
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// [ssOut] -- Output state set.
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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void CNFA::EpsClosure( UINT StateNum, CStateSet & ssOut )
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{
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CStateSet ssTraversed;
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ssOut.Add( StateNum );
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bool changed = true;
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while ( changed )
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{
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changed = false;
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for ( UINT i = ssOut.Count(); i > 0; i-- )
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{
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if ( !ssTraversed.IsMember( ssOut.State( i ) ) )
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{
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ssTraversed.Add( ssOut.State( i ) );
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Get( ssOut.State( i ) )->Move( ssOut, symEpsilon );
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changed = true;
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}
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}
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}
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::EpsClosure, public
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//
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// Synopsis: Computes the epsilon closure for state set [ssIn]
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//
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// Effects: States in the epsilon closure of [ssIn]
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// are added to the state set [ssOut].
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//
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// Arguments: [ssIn] -- Initial state set.
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// [ssOut] -- Output state set.
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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void CNFA::EpsClosure( CStateSet & ssIn, CStateSet & ssOut )
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{
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for ( UINT i = ssIn.Count(); i > 0; i-- )
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{
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EpsClosure( ssIn.State( i ), ssOut );
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}
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CDFA::IsFinal, public
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//
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// Arguments: [ss] -- State set
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//
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// Returns: true if some state in [ss] is final.
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//
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// History: 20-Jan-92 Kyleap Created
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//
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//--------------------------------------------------------------------------
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bool CNFA::IsFinal( CStateSet & ss )
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{
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bool fFinal = false;
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for ( UINT i = ss.Count(); i > 0 && !fFinal; i-- )
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{
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fFinal = (Get( ss.State( i ) )->IsFinal() != NULL);
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}
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return( fFinal );
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::Move, public
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//
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// Effects: Performs a non-deterministic move from every state
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// in [ssIn] on [symbol]. The new state set is in
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// [ssOut].
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//
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// Arguments: [ssIn] -- Initial state set.
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// [ssOut] -- Final state set.
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// [symbol] -- Transition symbol.
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//
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// History: 20-Jan-92 KyleP Created
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//
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//--------------------------------------------------------------------------
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void CNFA::Move( CStateSet & ssIn, CStateSet & ssOut, UINT symbol )
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{
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for ( UINT i = ssIn.Count(); i > 0; i-- )
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{
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Get( ssIn.State( i ) )->Move( ssOut, symbol );
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}
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::FindCharClasses, private
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//
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// Effects: Partitions the UniCode character space (2^16 characters)
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// into equivalence classes such that all characters in
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// a given class will have identical transitions in the NFA.
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//
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// Arguments: [wcs] -- Original regular expression string.
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//
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// History: 20-Jan-92 KyleP Created
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//
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// Notes: If case sensitivity is turned off, two ranges will be
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// added for characters with upper/lower case. Even though
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// both ranges react identically the mapping algorithm can
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// only deal with contiguous ranges of characters.
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//
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//--------------------------------------------------------------------------
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void CNFA::FindCharClasses( WCHAR const * wcs )
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{
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//
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// Scan the regex looking for characters with (potentially)
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// different transitions.
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//
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while ( *wcs )
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{
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switch ( *wcs )
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{
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case wcAnySingle:
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case wcAnyMultiple:
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case wcDOSDot:
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break;
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case wcEscape:
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{
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wcs++;
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switch ( *wcs )
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{
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case 0:
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throw ERROR_INVALID_PARAMETER;
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break;
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case wcAnySingle:
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case wcRepeatZero:
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case wcRepeatOne:
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case wcOr:
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case wcBeginParen:
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case wcEndParen:
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break;
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case wcBeginRepeat:
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for ( wcs++; *wcs; wcs++ )
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{
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if ( *wcs == wcEscape && *(wcs+1) == wcEndRepeat )
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{
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wcs++;
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break;
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}
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}
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break;
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case wcBeginRange:
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wcs++;
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//
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// Check the special cases of ^ and ]
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//
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if ( *wcs == wcInvertRange )
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wcs++;
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if ( *wcs == wcEndRange )
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{
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_chars.AddRange( *wcs, *wcs );
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wcs++;
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}
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for ( ; *wcs && *wcs != wcEndRange; wcs++ )
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{
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if ( *(wcs + 1) == wcRangeSep )
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{
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_chars.AddRange( *wcs, *(wcs+2) );
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}
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else
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{
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_chars.AddRange( *wcs, *wcs );
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}
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}
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if ( *wcs != wcEndRange )
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{
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throw ERROR_INVALID_PARAMETER;
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}
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break;
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default:
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_chars.AddRange( *wcs, *wcs );
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break;
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}
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break;
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}
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default:
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_chars.AddRange( *wcs, *wcs );
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break;
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}
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wcs++;
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}
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_chars.Prepare();
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}
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WCHAR * CNFA::_wcsNull = (WCHAR*)"";
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//+-------------------------------------------------------------------------
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//
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// Member: CNFA::Parse, private
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//
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// Synopsis: Creates a NFA from [wcs]
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//
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// Effects: Parses [wcs] until end of string or character wcHalt is
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// encountered. On exit, [iStart] and [iEnd] contain the
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// starting and ending states of the NFA, respectively.
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// [pwcsEnd] points to the last character of [wcs] that was
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// parsed.
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//
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// Arguments: [wcs] -- Regular expression.
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// [iStart] -- Starting state of NFA.
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// [iEnd] -- Ending state of NFA
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// [pwcsEnd] -- Last character of [wcs] that was parsed.
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// [wcHalt] -- Stop parsing if this character encountered.
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//
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// History: 20-Jan-92 KyleP Created
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// 08-Jun-98 SBens Fixed so that all top-level OR clauses
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// must terminate with symEndLine.
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//
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//--------------------------------------------------------------------------
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void CNFA::Parse( WCHAR const * wcs,
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UINT * iStart,
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UINT * iEnd,
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WCHAR const * * pwcsEnd,
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WCHAR wcHalt )
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{
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unsigned iCurrent;
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unsigned iNext;
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unsigned iLocalStart; // Used for */+/? repositioning
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bool fRepeat = false; // Used for +
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bool fTopLevel = (*iStart == 0); // true if at top level;
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*iEnd = 0;
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//
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// Get a starting state. *iStart == 0 implies this is the 'top-level'
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// parse of the regular expression (e.g. we're not parsing a
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// parenthesized subexpression.
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//
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if ( fTopLevel )
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{
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iCurrent = _iNextState;
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*iStart = _iNextState++;
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iLocalStart = 0;
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//
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// non-EGREP (DOS) regex match entire string.
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//
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if ( *wcs != wcAnyMultiple )
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{
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iNext = _iNextState;
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Get( iCurrent )->AddTransition( symBeginLine, _iNextState );
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_iNextState++;
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iCurrent = iNext;
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}
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else
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{
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//
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// Add a 'special' transition on the very first state to
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// eat up characters until we actually jump into the
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// regular expresion.
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//
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Get( iCurrent )->AddTransition( symAny, Get( iCurrent )->StateNumber() );
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}
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}
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else
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{
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iCurrent = *iStart;
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iLocalStart = *iStart;
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}
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|
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unsigned iOrStart = Get( iCurrent )->StateNumber();
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|
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//
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// wcsLocalStart tracks the piece of string to be repeated for wcZeroOrOne, etc.
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//
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|
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WCHAR const * wcsLocalStart = wcs;
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|
|
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//
|
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// Parse the regular expression until there is no more or a
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// termination character is hit.
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//
|
|
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for ( ; *wcs && *wcs != wcHalt; wcs++ )
|
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{
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switch ( *wcs )
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{
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case wcAnySingle:
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iNext = _iNextState;
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Get( iCurrent )->AddTransition( symAny, _iNextState );
|
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iLocalStart = Get( iCurrent )->StateNumber();
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wcsLocalStart = wcs;
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_iNextState++;
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iCurrent = iNext;
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break;
|
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|
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case wcAnyMultiple:
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//
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// Any single
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//
|
|
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iNext = _iNextState;
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Get( iCurrent )->AddTransition( symAny, _iNextState );
|
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iLocalStart = Get( iCurrent )->StateNumber();
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wcsLocalStart = wcs;
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_iNextState++;
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iCurrent = iNext;
|
|
|
|
//
|
|
// Repeat zero or more
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//
|
|
|
|
Get( iLocalStart )->AddTransition( symEpsilon,
|
|
Get( iCurrent )->StateNumber() );
|
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Get( iCurrent )->AddTransition( symEpsilon, iLocalStart );
|
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break;
|
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|
|
case wcEscape:
|
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{
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wcs++;
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|
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switch ( *wcs )
|
|
{
|
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case wcBeginParen:
|
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{
|
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UINT iLocalEnd;
|
|
|
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iLocalStart = Get( iCurrent )->StateNumber();
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wcsLocalStart = wcs - 1;
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wcs++; // Eat '('.
|
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Parse( wcs, &iLocalStart, &iLocalEnd, &wcs, wcEndParen );
|
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wcs--; // Provide character for loop to eat.
|
|
iCurrent = iLocalEnd;
|
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|
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break;
|
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}
|
|
|
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case wcEndParen:
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//
|
|
// Taken care of at outer level. Just backup so we hit the end.
|
|
//
|
|
|
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wcs--;
|
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break;
|
|
|
|
case wcBeginRepeat:
|
|
{
|
|
if ( wcHalt == wcBeginRepeat )
|
|
{
|
|
//
|
|
// Taken care of at outer level. Just backup so we hit the end.
|
|
//
|
|
|
|
wcs--;
|
|
}
|
|
else
|
|
{
|
|
//
|
|
// Setup: Bounds of repeated regex
|
|
//
|
|
|
|
WCHAR const * wcsStartRepeat = wcsLocalStart;
|
|
WCHAR const * wcsEndRepeat = wcs + 1;
|
|
|
|
//
|
|
// Setup: Repeat parameters.
|
|
//
|
|
|
|
unsigned cRepeat1, cRepeat2;
|
|
wcs++;
|
|
|
|
ParseRepeat( wcs, cRepeat1, cRepeat2 );
|
|
|
|
unsigned iLocalEnd;
|
|
|
|
//
|
|
// The minimum set has no epsilon transitions.
|
|
//
|
|
|
|
if ( cRepeat1 > 1 )
|
|
{
|
|
iLocalStart = Get( iCurrent )->StateNumber();
|
|
iLocalEnd = iLocalStart;
|
|
|
|
for ( unsigned i = 1; i < cRepeat1; i++ )
|
|
{
|
|
WCHAR const * wcsEnd;
|
|
|
|
iLocalStart = iLocalEnd;
|
|
iLocalEnd = 0; // Must be zero!
|
|
|
|
Parse( wcsLocalStart, &iLocalStart, &iLocalEnd, &wcsEnd, wcBeginRepeat );
|
|
|
|
if ( wcsEnd != wcsEndRepeat )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
iLocalEnd = Get( iCurrent )->StateNumber();
|
|
|
|
if ( cRepeat1 == cRepeat2 )
|
|
{
|
|
}
|
|
else if ( cRepeat2 == 0 )
|
|
{
|
|
|
|
Get( iLocalEnd )->AddTransition( symEpsilon, iLocalStart );
|
|
}
|
|
else if ( cRepeat2 > cRepeat1 )
|
|
{
|
|
for ( unsigned i = cRepeat1; i < cRepeat2; i++ )
|
|
{
|
|
WCHAR const * wcsEnd;
|
|
|
|
iLocalStart = iLocalEnd;
|
|
iLocalEnd = 0; // Must be zero!
|
|
|
|
Parse( wcsLocalStart, &iLocalStart, &iLocalEnd, &wcsEnd, wcBeginRepeat );
|
|
Get( iLocalStart )->AddTransition( symEpsilon, iLocalEnd );
|
|
|
|
if ( wcsEnd != wcsEndRepeat )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
|
|
iCurrent = iLocalEnd;
|
|
iLocalStart = 0;
|
|
wcsLocalStart = _wcsNull;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case wcOr:
|
|
// Top level 'OR' clauses must terminate with symEndLine.
|
|
if ( fTopLevel )
|
|
{
|
|
iNext = _iNextState;
|
|
Get( iCurrent )->AddTransition( symEndLine, _iNextState );
|
|
_iNextState++;
|
|
iCurrent = iNext;
|
|
}
|
|
|
|
if ( *iEnd == 0 )
|
|
{
|
|
//
|
|
// First part of OR clause.
|
|
//
|
|
|
|
*iEnd = Get( iCurrent )->StateNumber();
|
|
}
|
|
else
|
|
{
|
|
//
|
|
// Subsequent OR clause. Epsilon link to end
|
|
//
|
|
|
|
Get( iCurrent )->AddTransition( symEpsilon, *iEnd );
|
|
}
|
|
iCurrent = iOrStart;
|
|
wcsLocalStart = _wcsNull;
|
|
iLocalStart = 0;
|
|
break;
|
|
|
|
case wcBeginRange:
|
|
{
|
|
bool fReverse = false;
|
|
|
|
wcsLocalStart = wcs-1;
|
|
iNext = _iNextState;
|
|
wcs++; // Eat '['. ']' eaten by loop.
|
|
|
|
//
|
|
// Check the special cases of ^ and ]
|
|
//
|
|
|
|
if ( *wcs == wcInvertRange )
|
|
{
|
|
wcs++;
|
|
|
|
fReverse = true;
|
|
|
|
//
|
|
// Add all transitions, they will be removed later.
|
|
//
|
|
|
|
for ( UINT uiNext = _chars.TranslateRange( 1,
|
|
(USHORT) symLastValidChar );
|
|
uiNext != 0;
|
|
uiNext = _chars.TranslateRange( 0, (USHORT) symLastValidChar ) )
|
|
{
|
|
Get( iCurrent )->AddTransition( uiNext,
|
|
_iNextState );
|
|
}
|
|
|
|
}
|
|
|
|
if ( *wcs == wcEndRange )
|
|
{
|
|
if ( fReverse )
|
|
{
|
|
Get( iCurrent )->RemoveTransition( _chars.Translate( *wcs++ ),
|
|
_iNextState );
|
|
}
|
|
else
|
|
{
|
|
Get( iCurrent )->AddTransition( _chars.Translate( *wcs++ ),
|
|
_iNextState );
|
|
}
|
|
}
|
|
|
|
for ( ; *wcs && *wcs != wcEndRange; wcs++ )
|
|
{
|
|
if ( *(wcs + 1) == wcRangeSep )
|
|
{
|
|
if ( fReverse )
|
|
{
|
|
Get( iCurrent )->RemoveTransition(
|
|
_chars.TranslateRange( *wcs, *(wcs+2) ),
|
|
_iNextState );
|
|
}
|
|
else
|
|
{
|
|
Get( iCurrent )->AddTransition(
|
|
_chars.TranslateRange( *wcs, *(wcs+2) ),
|
|
_iNextState );
|
|
}
|
|
|
|
for ( UINT uiNext = _chars.TranslateRange( 0,
|
|
*(wcs+2) );
|
|
uiNext != 0;
|
|
uiNext = _chars.TranslateRange( 0, *(wcs+2) ) )
|
|
{
|
|
if ( fReverse )
|
|
{
|
|
Get( iCurrent )->RemoveTransition( uiNext,
|
|
_iNextState );
|
|
}
|
|
else
|
|
{
|
|
Get( iCurrent )->AddTransition( uiNext,
|
|
_iNextState );
|
|
}
|
|
}
|
|
|
|
wcs += 2;
|
|
}
|
|
else
|
|
{
|
|
if ( fReverse )
|
|
{
|
|
Get( iCurrent )->RemoveTransition(
|
|
_chars.Translate( *wcs ),
|
|
_iNextState );
|
|
}
|
|
else
|
|
{
|
|
Get( iCurrent )->AddTransition(
|
|
_chars.Translate( *wcs ),
|
|
_iNextState );
|
|
}
|
|
}
|
|
}
|
|
|
|
if ( *wcs != wcEndRange )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
|
|
iLocalStart = Get( iCurrent )->StateNumber();
|
|
_iNextState++;
|
|
iCurrent = iNext;
|
|
break;
|
|
}
|
|
|
|
case wcRepeatOne:
|
|
if ( iLocalStart == 0 )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
|
|
Get( iCurrent )->AddTransition( symEpsilon, iLocalStart );
|
|
break;
|
|
|
|
case wcRepeatZero:
|
|
if ( iLocalStart == 0 )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
Get( iLocalStart )->AddTransition( symEpsilon,
|
|
Get( iCurrent )->StateNumber() );
|
|
Get( iCurrent )->AddTransition( symEpsilon, iLocalStart );
|
|
break;
|
|
|
|
case wcRepeatZeroOrOne:
|
|
{
|
|
if ( iLocalStart == 0 )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
Get( iLocalStart )->AddTransition( symEpsilon,
|
|
Get( iCurrent )->StateNumber() );
|
|
break;
|
|
}
|
|
|
|
default:
|
|
iNext = _iNextState;
|
|
|
|
Get( iCurrent )->AddTransition( _chars.Translate( *wcs ),
|
|
_iNextState );
|
|
|
|
iLocalStart = Get( iCurrent )->StateNumber();
|
|
wcsLocalStart = wcs - 1;
|
|
_iNextState++;
|
|
iCurrent = iNext;
|
|
break;
|
|
}
|
|
|
|
break; // switch for wcEscape
|
|
}
|
|
|
|
default:
|
|
iNext = _iNextState;
|
|
|
|
Get( iCurrent )->AddTransition( _chars.Translate( *wcs ),
|
|
_iNextState );
|
|
|
|
//
|
|
// In non-EGREP (DOS) syntax dot '.' is funny. It will match
|
|
// a dot, but if you're at the end of string it will also match
|
|
// end. So *.txt will look for strings with zero or more
|
|
// characters followed by '.txt' but *. will find any names
|
|
// without an extension and with no trailing dot.
|
|
//
|
|
|
|
if ( *wcs == wcDOSDot )
|
|
{
|
|
Get( iCurrent )->AddTransition( symEndLine, _iNextState );
|
|
}
|
|
|
|
iLocalStart = Get( iCurrent )->StateNumber();
|
|
wcsLocalStart = wcs;
|
|
_iNextState++;
|
|
iCurrent = iNext;
|
|
break;
|
|
}
|
|
}
|
|
|
|
//
|
|
// non-EGREP (DOS) regex match entire string.
|
|
//
|
|
|
|
if ( wcHalt == 0 && *(wcs-1) != wcAnyMultiple )
|
|
{
|
|
iNext = _iNextState;
|
|
Get( iCurrent )->AddTransition( symEndLine, _iNextState );
|
|
iLocalStart = 0;
|
|
wcsLocalStart = _wcsNull;
|
|
_iNextState++;
|
|
iCurrent = iNext;
|
|
}
|
|
|
|
//
|
|
// If we haven't had an OR clause yet, then set iEnd
|
|
//
|
|
|
|
if ( *iEnd == 0 )
|
|
{
|
|
//
|
|
// First part of OR clause.
|
|
//
|
|
|
|
*iEnd = Get( iCurrent )->StateNumber();
|
|
}
|
|
else
|
|
{
|
|
//
|
|
// Subsequent OR clause. Epsilon link to end
|
|
//
|
|
|
|
Get( iCurrent )->AddTransition( symEpsilon, *iEnd );
|
|
}
|
|
|
|
if ( pwcsEnd )
|
|
{
|
|
*pwcsEnd = wcs + 1; // Eat halt character.
|
|
}
|
|
|
|
if( *wcs != wcHalt )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
}
|
|
|
|
void CNFA::ParseRepeat( WCHAR const * & wcs, unsigned & cRepeat1, unsigned & cRepeat2 )
|
|
{
|
|
cRepeat1 = 0;
|
|
cRepeat2 = 0;
|
|
|
|
for ( ; *wcs && isdigit(*wcs); wcs++ )
|
|
{
|
|
cRepeat1 *= 10;
|
|
cRepeat1 += *wcs - '0';
|
|
}
|
|
|
|
if ( cRepeat1 == 0 || cRepeat1 > 255 )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
|
|
if ( *wcs == ',' )
|
|
{
|
|
wcs++;
|
|
|
|
if ( *wcs == wcEscape && *(wcs+1) == wcEndRepeat )
|
|
{
|
|
wcs++;
|
|
}
|
|
else
|
|
{
|
|
for ( ; *wcs && isdigit(*wcs); wcs++ )
|
|
{
|
|
cRepeat2 *= 10;
|
|
cRepeat2 += *wcs - '0';
|
|
}
|
|
|
|
if ( cRepeat2 == 0 || cRepeat2 > 255 )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
|
|
if ( *wcs != wcEscape || *(wcs+1) != wcEndRepeat )
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
else
|
|
{
|
|
wcs++;
|
|
}
|
|
}
|
|
}
|
|
else if ( *wcs == wcEscape && *(wcs+1) == wcEndRepeat )
|
|
{
|
|
wcs++;
|
|
cRepeat2 = cRepeat1;
|
|
}
|
|
else
|
|
{
|
|
throw ERROR_INVALID_PARAMETER;
|
|
}
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::CDFA, public
|
|
//
|
|
// Synopsis: Constructs a DFA from a NFA.
|
|
//
|
|
// Arguments: [pwcs] -- Regular expression (passed to NFA)
|
|
// [fCaseSens] -- true if case-sensitive search
|
|
//
|
|
// History: 20-Jan-92 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CDFA::CDFA( WCHAR const * pwcs, bool fCaseSens )
|
|
: _nfa( pwcs, fCaseSens ),
|
|
_xs( _nfa.NumStates() ),
|
|
_cState( _nfa.NumStates() ),
|
|
_pStateTrans( 0 ),
|
|
_pStateFinal( 0 )
|
|
{
|
|
CommonCtor();
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::CDFA, public
|
|
//
|
|
// Synopsis: Copy constructor
|
|
//
|
|
// Arguments: [pwcs] -- Regular expression (passed to NFA)
|
|
// [fCaseSens] -- true if case-sensitive search
|
|
//
|
|
// History: 20-Jan-92 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CDFA::CDFA( CDFA const & src )
|
|
: _nfa( src._nfa ),
|
|
_xs( src._nfa.NumStates() ),
|
|
_cState( src._nfa.NumStates() ),
|
|
_pStateTrans( 0 ),
|
|
_pStateFinal( 0 )
|
|
{
|
|
CommonCtor();
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::CommonCtor, private
|
|
//
|
|
// Synopsis: Code common to both constructors.
|
|
//
|
|
// History: 13-Jul-95 KyleP Snarfed from constructor
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
void CDFA::CommonCtor()
|
|
{
|
|
//
|
|
// Add initial state.
|
|
//
|
|
|
|
CStateSet ss;
|
|
|
|
_nfa.EpsClosure( _nfa.StartState(), ss );
|
|
|
|
_stateStart = _xs.XlatToOne( ss );
|
|
|
|
//
|
|
// Intialize translation table.
|
|
//
|
|
|
|
int cEntries = (_cState + 1) * ( _nfa.Translate().NumClasses() + 1 );
|
|
|
|
_pStateTrans = new UINT [ cEntries ];
|
|
_pStateFinal = new bool [ _cState + 1 ];
|
|
|
|
memset( _pStateTrans, 0xFF, cEntries * sizeof(_pStateTrans[0]) );
|
|
RtlZeroMemory( _pStateFinal, (_cState + 1) * sizeof(_pStateFinal[0]) );
|
|
|
|
for ( int i = _cState; i >= 0; i-- )
|
|
{
|
|
AddTransition( i, 0, stateUndefined );
|
|
}
|
|
|
|
Add( _stateStart, _nfa.IsFinal( ss ) );
|
|
|
|
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::~CDFA, public
|
|
//
|
|
// Synopsis: Clean up DFA. Free state tables.
|
|
//
|
|
// History: 20-Jun-92 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CDFA::~CDFA()
|
|
{
|
|
delete _pStateTrans;
|
|
delete _pStateFinal;
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::Recognize, public
|
|
//
|
|
// Arguments: [wcs] -- Input string.
|
|
//
|
|
// Returns: true if [wcs] is matched by the regular expression.
|
|
//
|
|
// History: 20-Jan-92 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
bool CDFA::Recognize( WCHAR * wcs )
|
|
{
|
|
//////////
|
|
// Modified from original version to handle a NULL string.
|
|
//////////
|
|
if (!wcs) { return false; }
|
|
|
|
UINT CurrentState = _stateStart;
|
|
UINT LastState = CurrentState;
|
|
bool fFinal = IsFinal( CurrentState );
|
|
WCHAR wcCurrent = symBeginLine;
|
|
|
|
while ( !fFinal )
|
|
{
|
|
UINT NextState = Move( CurrentState, wcCurrent );
|
|
|
|
if ( NextState == stateUncomputed )
|
|
{
|
|
CStateSet ssCurrent;
|
|
CStateSet ssNew;
|
|
CStateSet ssClosed;
|
|
|
|
_xs.XlatToMany( CurrentState, ssCurrent );
|
|
|
|
_nfa.Move( ssCurrent, ssNew, wcCurrent );
|
|
|
|
if ( ssNew.Count() == 0 )
|
|
{
|
|
NextState = stateUndefined;
|
|
AddTransition( CurrentState, wcCurrent, NextState );
|
|
}
|
|
else
|
|
{
|
|
_nfa.EpsClosure( ssNew, ssClosed );
|
|
|
|
NextState = _xs.XlatToOne( ssClosed );
|
|
|
|
if ( !IsComputed( NextState ) )
|
|
{
|
|
Add( NextState, _nfa.IsFinal( ssClosed ) );
|
|
}
|
|
|
|
AddTransition( CurrentState, wcCurrent, NextState );
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if ( NextState == stateUndefined )
|
|
{
|
|
return( false );
|
|
}
|
|
|
|
LastState = CurrentState;
|
|
CurrentState = NextState;
|
|
|
|
fFinal = IsFinal( CurrentState );
|
|
|
|
|
|
//
|
|
// If we ran out of string then just keep going, appending
|
|
// end-of-string symbols. Unfortunately the string is conceptually
|
|
// a set of characters followed by an arbitrary number of
|
|
// end-of-string symbols. In non-EGREP the end-of-string symbol
|
|
// may actually cause multiple state transitions before reaching
|
|
// a final state. In non-EGREP (DOS) mode we stop only when we
|
|
// are no longer 'making progress' (moving to new states) on
|
|
// end-of-string. I haven't completely convinced myself this
|
|
// algorithm is guaranteed to terminate.
|
|
//
|
|
|
|
if ( wcCurrent == symEndLine )
|
|
{
|
|
if ( LastState == CurrentState )
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
wcCurrent = *wcs++;
|
|
|
|
//
|
|
// After we've exhausted the string, append the special
|
|
// end-of-line character.
|
|
//
|
|
|
|
if ( wcCurrent == 0 )
|
|
{
|
|
wcCurrent = symEndLine;
|
|
}
|
|
else
|
|
{
|
|
wcCurrent = (WCHAR)_nfa.Translate().Translate( wcCurrent );
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
return( fFinal );
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CDFA::Add, private
|
|
//
|
|
// Synopsis: Adds a new state the the DFA.
|
|
//
|
|
// Arguments: [state] -- State number
|
|
// [fFinal] -- true if state is a final state.
|
|
//
|
|
// History: 20-Jan-92 KyleP Created
|
|
//
|
|
// Notes: All transitions for the new state are initially uncomputed.
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
void CDFA::Add( UINT state, bool fFinal )
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{
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if ( state > _cState )
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{
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//
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// Since the number of states required will probably grow at
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// a slow rate, increase the size of the array in a linear
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// fashion.
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UINT const DeltaState = 10;
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UINT * oldStateTrans = _pStateTrans;
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bool * oldStateFinal = _pStateFinal;
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UINT oldcState = _cState;
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UINT oldcEntries = (_cState + 1) *
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( _nfa.Translate().NumClasses() + 1 );
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_cState += DeltaState;
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UINT cEntries = (_cState + 1) * ( _nfa.Translate().NumClasses() + 1 );
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_pStateTrans = new UINT [ cEntries ];
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_pStateFinal = new bool [ _cState + 1 ];
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//
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// Initilize new state tables...
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//
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memcpy( _pStateTrans, oldStateTrans, oldcEntries * sizeof( UINT ) );
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memcpy( _pStateFinal, oldStateFinal, oldcState * sizeof( bool ) );
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memset( _pStateTrans + oldcEntries, 0xFF, (cEntries - oldcEntries)*sizeof(_pStateTrans[0]) );
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RtlZeroMemory( _pStateFinal + oldcState, (_cState + 1 - oldcState)*sizeof(_pStateFinal[0]) );
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for ( UINT i = _cState - DeltaState + 1; i <= _cState; i++ )
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{
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AddTransition( i, 0, stateUndefined );
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}
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//
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// ...and destroy the old
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//
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delete oldStateTrans;
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delete oldStateFinal;
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}
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//
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// All states are set to stateUncomputed above, except the 'undefined' flag-state.
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//
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|
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AddTransition( state, 0, stateUncomputed );
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_pStateFinal[state] = fFinal;
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}
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